1. Field of the Invention
The present invention relates to a thermal head and a manufacturing method thereof, and more particularly to a thermal head which does not scratch a print paper and assures a high print quality, and a manufacturing method thereof.
2. Description of The Prior Art
A structure of a prior art thermal head is shown in FIGS. 1 and 2.
In a usual thermal head 1, a glaze layer 6 which serves for heat insulation is formed on a ceramic substrate 2, and a heat generating resistor 3 and electrodes 4 are formed on the glaze layer 6 a protection layer 5 for preventing oxidization and abrasion are formed on the heat generating resistor 3 and the electrodes 4 to cover them.
As shown in FIG. 3, the ceramic substrate 2 having an area corresponding to a plurality of heads is prepared, on which the glaze layer 6, the heat generating resister 3 and the electrodes 4 are formed, and it is cut along cut lines 7 shown by broken lines into individual thermal heads 1.
When the thermal head thus constructed is used for printing, it scratches a thermal print paper or a thermal transfer ink ribbon because it has a sharp edge at the cut portion along the cut line 7, and hence print quality is deteriorated.
This is illustrated in FIG. 4, in which numeral 8 denotes a print paper which is scratched by an edge 9 of the thermal head 1. The thermal head 1 is usually mounted on a heat sink 10 as shown in FIG. 5. Accordingly, a side 9a of the thermal head 1 slightly protrudes from a top surface of the heat sink 10 as shown in FIG. 5. Thus, when the thermal head 1 is moved left beyond a side edge 11 of the second paper 8 and then moved reversely, the side 9a of the thermal head 1 scratches the side edge 11.
In order to prevent such scratch, the thermal head 1 may be constructed not to protrude from the surface of the heat sink 10. However, it is very difficult to design the thermal head 1 having non-protruding side 9a because of the precision with which an anti-scratch spacer must be arranged on the heat sink 10 or the thermal head 1.